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Full text of "The manufacture and properties of iron and steel"

354
METALLURGY OP IKON AND STEEL.
part of the same rod pulled in the usual manner. It is not the intention to advocate the use of such a high content of manganese, for the general conclusion of metallurgists points to as low a proportion as will ensure good working in the rolls. In the case of ingots rolled directly into plates, the allowable content. is limited by the requirement that the steel shall boil in the molds, but it does not follow, because bad results accompany higher manganese in such practice, that the quality of the product is proportionally deteriorated when the ingot is roughed down .and reheated.
The effect of large proportions of manganese upon steel is one of the most curious phenomena, in metallurgy. As the content rises over 1.5 or 2 per cent, the metal becomes brittle and almost worthless, and further additions do not better the matter until an alloy is reached with about 6 or 7 per cent, manganese. From this point the metal is not only extremely hard, but possesses the rather peculiar property of becoming very much tougher after quenching in water, without any great change in hardness. The physical properties of manganese steel are shown in Table XYII-G, which is taken from an article by Hadfield.* This alloy is used in the making of
TABLE XYII-G. Forged Steel Containing from .83 to 19 Per Cent. Manganese. f
Composition ; per cent.
Natural.
Quenched in water.
Annealed.
"~0i S m""1 2 WW 9-
dSd
Ssgl gs&
p
Elongation in 8 inches per cent.
-*!
*s ra H
rt .
Orf-P
B 2 fl 1-So
9s 2
 rft
ngth; nds pe inc
te t s
stre pou squ
tion ches nt.
on n 8 er
.20
.40
.40
^2
.47
.61
.85
1.10
.92
.85
...1.10
1.24
1.54
1.83
1.60
.03 .15 .09 .37 .44 .80 .28 .16
..82 .16 .16
.83
2.80
8.89
6.95
7.22
9.87
10.60
12.60
12.81
14.01
14.48
15.06
18.40
18.55
19.10
78920
125440
85120
56000
60480
78920
76160
87860
87860
80640
87860
109760
J14240
96820
110480
31 6 1 2
2 5 4 2 5 2 1 2 1
1
2 2 15 17 27 37 44 87 81 10 5 4
91840
*See also The Mineral Industry, Vol. IV, for an essay on Alloys of Iron, by B. A Hadfleld. t Condensed from Hadfleld, Journal I. and.8.1., Vol. II, 1888, p. 70.